Probability & Combinatorics
Intermediate

Conditional Probability

Probability of A given that B has occurred.

Formula

P(A∣B)=P(A∩B)P(B)P(A|B) = \frac{P(A \cap B)}{P(B)}

Variables

A,BEvents
P(B)Nonzero

Example

Updates probability with new information

Did You Know?

Conditional probability is the foundation of Bayesian reasoning.

probabilityconditional